Sodium alginate-grafted submicrometer particles display enhanced reversible aggregation/disaggregation properties
Faezeh Sabri1, Kevin Berthomier1, Antoine Marion1
1Research Center for High Performance Polymer and Composite Systems (CREPEC), Department of Chemical Engineering, Polytechnique Montréal, Montréal, Québec, H3C 3A7, Canada.
Carbohydrate Polymers
|May 27, 2018
Summary
Submicrometer silica particles modified with sodium alginate (SA) exhibit pH-dependent reversible aggregation. This enhances particle separation processes by enabling controlled aggregation and disaggregation in aqueous solutions.
Area of Science:
- Materials Science
- Colloid and Surface Chemistry
Background:
- Submicrometer particles are crucial in various applications, but controlling their aggregation and separation can be challenging.
- Surface modification of particles offers a route to tune their properties, including interparticle interactions.
Purpose of the Study:
- To develop and characterize submicrometer silica particles with surface-grafted sodium alginate (SA) for enhanced and reversible aggregation/disaggregation.
- To investigate the influence of pH on the aggregation behavior of SA-modified silica particles.
- To assess the impact of SA grafting on particle sedimentation rates.
Main Methods:
- Functionalization of 300 nm silica particles with an aminosilane coupling agent.
- Grafting of pH-sensitive sodium alginate (SA) onto the silica surface.
- Characterization using zeta potential, X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared spectroscopy (FTIR).
- Evaluation of aggregation, disaggregation, and sedimentation properties at different pH values.
Main Results:
- SA-modified silica particles demonstrated significantly enhanced aggregation at acidic pH (pH 3.0) compared to unmodified silica.
- A 10-fold increase in average aggregate diameter was observed for SA-modified particles at acidic pH.
- The aggregation process was reversible, with aggregates redispersing upon increasing the pH to 7.0.
- SA-modified particles exhibited a significantly faster and complete sedimentation rate at pH 3.0.
Conclusions:
- Surface grafting of sodium alginate onto submicrometer silica particles effectively enhances and controls reversible aggregation/disaggregation in aqueous solutions.
- The pH-sensitive nature of SA allows for tunable interparticle interactions, improving particle separation efficiency.
- This approach demonstrates the utility of natural macromolecules for modifying particle behavior and optimizing separation processes.
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